Who could succeed Jamie Dimon?

FORTUNE — In an ideal world, it would be great to be king. But it’s no news flash that imperial chairman-CEOs are not the most effective leaders. Consultant and author Jim Collins demonstrated that long ago.

But in the last couple of years, the shift in board thinking on how much control a CEO should have has been remarkable. Regarding the issue of having an independent chair, the old rhetoric was “one size doesn’t fit all.” It may work for some companies, but not all, the thinking went. Some board members really believed the line, but for others, it was resignation to the fact that, as board members, they didn’t believe they had the muscle to push the idea through.

Today, the majority of board members I speak with, however, don’t just embrace the idea of having a board chair that’s independent of the top manager. They actively sympathize with directors who don’t have that arrangement.

Disney DIS shareholders missed out on splitting the CEO and chair roles (the proposal won 36% of the vote), and Jamie Dimon, CEO of J.P. Morgan JPM, is fighting to keep his chairmanship. Warren Buffett supports this — and, on this, he is wrong.

At this point, it’s not a question of whether companies should have an independent chair but of identifying the right person for the chair role. Independence from management — not just separation — is what more and more shareholders and board members are looking for today. Ray Lane was not a truly independent chair at HP, nor was Ray Irani at Occidental. Lane lost his chairmanship this year. Irani recently lost his board seat and chair position.

And chair succession is a serious problem for weak boards. HP had to install an interim chair this year and is presumably looking for a new board member who can fill those boots.

If at J.P. Morgan shareholders vote to split the chair and CEO roles, the company will face the same dilemma. As strong a CEO as Lee Raymond was at ExxonMobil xom, his weakness as presiding director at J.P. Morgan has been a black mark for the bank’s ineffective board.

As with HP hpq, it’s time for new board members at the megabank. Maybe they should consider former CFTC head Brooksley Born, former U.S. representative Brad Miller, or former bank regulator Bill Black. All three know a thing or two about banks, oversight, and regulation and would instill confidence in investors.

Managing chair succession is new territory for many boards. But it’s a welcome change.